WO1997011270A1

WO1997011270A1 - Fuel injection valve

Info

Publication number: WO1997011270A1
Application number: PCT/DE1996/001302
Authority: WO
Inventors: Uwe Grytz; Stefan Lauter
Original assignee: Robert Bosch Gmbh
Priority date: 1995-09-21
Filing date: 1996-07-18
Publication date: 1997-03-27
Also published as: JPH10509495A; DE19535047A1; EP0823020B1; EP0823020A1; DE59607134D1; US5819707A

Abstract

A fuel injection valve (13) for injecting fuel into an internal combustion engine in which at least two separate streams of fuel (14) are directed into different inlet channels or ports of a cylinder. The fuel injection valve (13) has a front attachment (42) in the wall of which a blocking component (83) is slidingly fitted, at the sliding section (82) of which facing an air chamber (67) prevail the pressure in the intake pipe upstream of a throttle valve while the intake pipe pressure acts in the opposite direction downstream of said valve. When the pressure difference is adequate the blocking component (83) is pushed far enough to the left to block at least one injection aperture (53) of the fuel injection valve (13) and a feed channel (78) in the front attachment (42). Thus only the one open inlet valve of a cylinder (1) of the engine is supplied with fuel via the at least one open injection aperture (53) and the open feed channel (78).

Description

Fuel injector

State of the art

The invention relates to a fuel injector according to the preamble of the main claim. A fuel injection valve is already known (US Pat. No. 4,982,716), in which the fuel jets directed at different intake ports of a cylinder are always sprayed off at the same time. However, this results in the disadvantage that when one of the at least two inlet valves is switched off in certain operating states of the internal combustion engine, such as idling and lower partial load, in order to improve the operating behavior of the internal combustion engine with regard to consumption and exhaust gas emission, at least one of the separated fuel jets undesirably the closed inlet valve hits.

In this fuel injector, two separate fuel jets are generated in that a single fuel jet strikes an impact surface downstream of the valve seat and is divided into two separate fuel jets by means of a beam splitter.

Also known from EP-PS 0 242 978 is a fuel injector with a perforated disk arranged downstream of the valve seat surface, in which six spray openings are provided, the individual jets emerging from three spray openings being directed towards one another in such a way that two separate ones

Fuel jets result, wherein each fuel jet is directed into an inlet channel of a cylinder of the internal combustion engine. This fuel injector too the fuel is injected into the two intake ports of each engine cylinder via the two separate fuel jets even when one of the intake valves is closed.

A fuel injector is also known (SAE Technical Paper Series 920 294, 1992; Development of Air-Assisted Injector System), on which an adapter with a jet splitter is provided, by means of which a fuel sprayed from the injector is split into two

Fuel jets is divided, to which air is supplied for processing via air channels, which air can be controlled by a control valve which branches off from a bypass line around the throttle valve in the intake pipe of the internal combustion engine. The control valve opens and closes the air line to the fuel injection valves with one closing element and the bypass line around the throttle valve with another closing element.

Advantages of the invention

The fuel injector according to the invention with the characterizing features of the main claim has the advantage that fuel is supplied to each cylinder of the internal combustion engine in a simple manner under certain operating conditions of the internal combustion engine, such as idling and lower partial load, only via the open intake valve or the opened intake valves, while these certain operating conditions before the closed intake valves or the closed intake valve, no fuel is stored upstream. In addition to fuel consumption, this also allows the proportion of harmful exhaust gas components to be reduced and the transition behavior between the operating states to be improved. The measures listed in the subclaims allow advantageous developments and improvements of the fuel injector specified in the main claim.

It is particularly advantageous on the

To arrange fuel injection valve a header in which the shut-off element is movably mounted. As a result, no design change to existing fuel injection valves is required, but only an adaptation of a suitable attachment body to the respective fuel injection valve. It is also advantageous for the shut-off element to be displaced by air which is fed to the fuel injection valve for processing the sprayed-off fuel. It is also advantageous to use a control valve in the air line to the shut-off element, through which the air line can be partially or completely closed in order to actuate the shut-off element exactly according to the respective needs of the internal combustion engine.

drawing

Exemplary embodiments of the invention are shown in simplified form in the drawing and in the following

Description explained in more detail. FIG. 1 a shows a fuel injection valve arranged on an inlet duct of an internal combustion engine, to which an air line with a control valve is connected, FIG. 1 b shows a schematic illustration of the injection of two separate ones

Jets of fuel through a fuel injection valve into two inlet channels of a cylinder of an internal combustion engine, FIGS. 2a to 2c a control valve in different switching positions, FIG. 3 a first embodiment of an embodiment according to the invention

Fuel injector with a shut-off element in the non-locking position, Figure 4 shows a section along the line IV-IV in FIG. 3, FIG. 5 a fuel injection valve according to the first exemplary embodiment according to FIG. 3 with a shut-off element located in the blocking position, FIG. 6 a section along the line VI-VI in FIG. 5, FIG. 7 a second exemplary embodiment of a stop valve according to the invention provided fuel injector, the shut-off element is in the blocking position, Figure 8 shows a section along the line VIII-VIII in Figure 7.

Description of the embodiments

FIG. 1 a shows a cylinder of a mixture-compressing, spark-ignition internal combustion engine, which has at least one inlet opening 2, which is opened or closed by an inlet valve 3. To improve the

Efficiency and to reduce the exhaust gas components of the internal combustion engine, in particular through lean operation and charge stratification, today the cylinders of the internal combustion engine are often provided with two or more intake valves and exhaust valves. Figure lb shows a cylinder with two inlet openings 2, in which the inlet valves 3 have been omitted for ease of illustration. A spark plug 5 is used to ignite the fuel-air mixture compressed in the cylinder 1, and two outlet openings 6, which are not shown

Exhaust valves are controlled, lead to the exhaust pipe 7 of the internal combustion engine. Separated by a partition 9, an inlet duct 10 leads to each inlet opening 2, the two inlet ducts 10 upstream of the partition 9 leading to one assigned to the respective cylinder

Combine single suction pipe 11. An injection end of a fuel injection valve 13, which injects two separate fuel jets 14, partially projects into the individual intake manifold 11, one fuel jet 14 in each case being directed in the direction of an inlet channel 10 or an inlet opening 2. As has been described for FIG. 1b, the cylinder 1 also has two intake valves 3 and two in FIG Inlet openings 2 through a single

Fuel injector 13 are supplied with fuel. In another embodiment, however, the cylinder 1 can also have only one inlet valve 3 and one inlet opening 2, while the fuel injection valve 13 is nevertheless designed such that it jets off at least two separate fuel jets in the direction of the inlet channel 10 and the inlet opening 2, respectively. The direction of the separate fuel jets 14 can be selected very precisely and adapted to a favorable operating behavior of the internal combustion engine.

The individual intake pipe 11 starts from a distributor 15, from which the individual intake pipes also branch off to the other cylinders, not shown, of the internal combustion engine. Upstream of the distributor is the intake manifold 17 with the throttle valve 18, which can be actuated by the driver by means of an accelerator pedal, not shown. Upstream of the throttle valve 18, an air bypass 19 branches off from the intake manifold 17, in which a control valve 21 is arranged, the control body 22 of which can continuously assume various positions in order to close the air bypass 19, a connection from the air bypass to an air line 23 leading to the fuel injection valve 13 and then at the same time establish a connection from the air bypass 19 to an inflow line 25 leading downstream of the throttle valve 18 to the intake manifold 17 and finally to completely block the connection to the air line 23 and only keep the connection to the inflow line 25 open. The control valve 21 is actuated, for example, by an electric motor and controlled by an electronic control device 26 via electrical lines. The electronic control unit 26 also controls the electromagnetically actuated fuel injector 13 via electrical lines. Measured values of operating parameters of the operating parameters are converted into electronic signals Internal combustion engine supplied, for example, the speed 27, the load 28 according to the angle of rotation of the throttle valve 18, the temperature 29 of the internal combustion engine, the oxygen concentration 30 in the exhaust pipe 7 and others.

In FIGS. 2a, 2b and 2c, the control valve 21 designed as a rotary slide valve and, for example, driven by an electric motor according to FIG. 1 a is shown once again in simplified form and shown in different control positions, the reference symbols chosen in FIG. 1 a being retained. The control body 22, which is designed as a rotary slide valve, can be rotated by an electric motor (not shown) and has the shape of a circular segment in cross section with an indentation 32 which is delimited by a first sealing lip 33 and a second sealing lip 34 of the control body 22. When the control body 22 rotates clockwise, the first sealing lip 33 leads the second sealing lip 34. The control body 22 is rotatably mounted in a working space 36, to which the air bypass 19, the air line 23 and the inflow line 25 are connected. The air bypass 19 is delimited at its mouth to the working space 36 by a first sealing surface 37 and in a clockwise direction by a second sealing surface 38. The second sealing surface 38 also delimits the mouth of the air line 23 into the working space 36, which is delimited clockwise by a third sealing surface 39. In FIG. 2a, the control body 22 assumes a position in which the first sealing lip 33 partially covers the second sealing surface 38 and the third sealing surface 39 and the second sealing lip 34 covers the first sealing surface 37, so that in each case the connection from the air bypass 19 to the air line 23 and the inflow line 25 is interrupted. If the control body 22 is now turned clockwise in idle and lower part-load operation of the internal combustion engine, the second sealing lip 34 initially continues to cover the first sealing surface 37, while the first sealing lip 33 extends from the second sealing surface 38 moved away and thus opens a connection from the air bypass 19 to the air line 23 via the indentation 32. FIG. 2 b shows a position of the control body 22 in which a flow connection from the air bypass 19 to the air line 23 through the control body 22 is open, but the second sealing lip 34 is just overlapped with the first sealing surface 37 so that no air flow from the air bypass 19 to the inlet line 25. If the control body 22 is rotated clockwise beyond the position shown in FIG. 2b, then the second sealing lip 34 moves away from the first sealing surface 37, so that now in addition to the flow from the air bypass 19 to the air line 23, the flow path from the air bypass 19 to the inlet line 25 is opened. Such a position of the control body 22 is shown in FIG. 2c. In order to ensure in the event of a fault in the electronic control unit or on the electrical lines or on the electric motor that the internal combustion engine continues to be operated in a so-called emergency operation, it can be expedient to use a return spring (not shown), starting from a position according to FIG to the extent that either the first sealing lip 33 out of contact with the third sealing surface 39 or the second sealing lip 34 out of contact with the first sealing surface 37 or both the first

Sealing lip 33 is out of contact with the third sealing surface 39 and the second sealing lip 34 is out of contact with the first sealing surface 37, so that either a flow connection from the air bypass 19 to the air line 23 or to the inflow line 25 or to these two is established.

In FIG. 3, an example of an otherwise already known fuel injection valve 13 for fuel injection systems of mixture-compressing spark-ignition internal combustion engines is shown in part, the one at its spray end 41, for example Plastic-made attachment body 42 carries. The spray end 41 of the fuel injection valve 13 is formed in a nozzle body 43 which is provided with a longitudinally extending guide channel 45 in which a movable valve closing member 46, for example a valve needle, is slidably mounted. Facing the spray end 41, the guide channel 45 merges into a valve seat surface 47 with which the valve closing member 46 cooperates. In the flow direction, the valve seat surface 47 merges into an outflow opening 49 which extends up to one

Nozzle body end face 50 extends. In the exemplary embodiment shown, a spray orifice plate 51 bears against the nozzle face end face 50 and is tightly connected to it, for example by a circumferential sealing seam at a radial distance from the outflow opening 49. In the top cover with the outflow opening 49, at least two spraying holes 53 are provided in the spray hole disk 51 in the exemplary embodiment according to FIG. 3, which extend up to a lower end face 54 of the spray hole disk 51. It is not a condition that at least two spray holes 53 are formed in the spray hole disk 51. In a manner not shown, only one spray hole 53 can also be formed in the spray hole disk 51, the fuel emerging from the one spray hole being divided downstream into two individual jets by a beam splitter, as is already known from the known fuel injection valves described in the introduction to the description. The spray hole disk 51 is also not a requirement, but a fuel injection valve can also be used in which no spray hole disk is provided, but in which the fuel is sprayed out via the outflow opening 49 or at least two spraying holes which are connected to the outflow opening 49 and are formed on the nozzle body end face 50 becomes. The actuation of the

Fuel injection valve is carried out in a known manner, for example electromagnetically. For the axial movement of the Valve closing member 46 and thus for opening against the spring force of a return spring, not shown, or closing the fuel injector, an electromagnetic circuit with a solenoid, not shown, an armature and a core is used. The armature is connected to the end of the valve closing member 46 facing away from the valve seat surface 47 and is aligned with the core.

The attachment body 42 consists, for example, of a stepped tubular air guide body 55 and a spray body 57. The spray body 57 is pot-shaped with a base 58, which is followed by an annular rim 59 which surrounds the spray end 41 of the fuel injection valve 13. At the spray end 41 of the fuel injection valve 13, a circumferential locking groove 61 is formed, into which an at least partially circumferential locking nose on the inner wall of the ring rim 49 engages and thus fixes the spray body 57 at the spray end 41 of the fuel injection valve. In an annular groove 63 provided on the circumference of the spray body 57, an elastic sealing ring 65 is arranged, against which a stepped inner wall 66 of the air guide body 55 lies tightly under radial pressure. The air guide body 55 extends in the axial direction beyond the ring rim 59 and partially over the housing, to which it bears in a sealed manner in a manner not shown. The inner wall 66 of the air guide body 55 has a radial distance from the spray body 57 and the housing of the fuel injector, with the exception of the sealed points on the sealing ring 65 and on the circumference of the housing of the fuel injector 13, so that between the inner wall 66 and the outside of the fuel injector and the Ring edge 59 an annular air space 67 is formed, which with the air line 23 via an air connector 69 in

Connection is established. Axially approximately in the area of the bottom 58 of the spray body 57 is on the circumference of the air guide body 55 an annular groove 70 is formed, in which an elastic sealing ring 71 is arranged, which when the fuel injection valve 13 is inserted with the attachment body 42 arranged thereon in a valve channel 73 (FIG. 1 a) of the wall of the individual intake pipe 11, seals the intake pipe atmosphere from the outside. The bottom 58 of the spray body 57 has a dome 74 which rises in the direction of the spray hole disk 51, between the end face 75 of which faces the spray hole disk 51 and the lower end face 54 of the spray hole disk, a gap 76 is formed. Starting from the end face 75 of the dome 74, at least two guide channels 78 extend through the bottom 58 of the spray body 57 and run approximately in alignment with the associated spray holes 53 such that the distance to one in the direction of flow

Valve longitudinal axis 79 and each other is larger. In the exemplary embodiment shown, two guide channels 78 are provided, a fuel jet 14 emerging from one of the spray holes 53 being sprayed through each guide channel in accordance with the dash-dotted lines. However, each fuel jet 14 can also be formed by combining two or more individual jets emerging from individual injection holes. At least one third guide channel 78 can also be formed in the spray body 57 to form another

Fuel jet 14 may be provided. Transversely to the longitudinal axis 79 of the valve penetrates the ring rim 59 of the spray body 57, a slide channel 80, in which a slide section 82 of a shut-off element 83 is mounted essentially tightly but displaceably. The shut-off element 83 also has a tongue-shaped web section 84 which is connected to the cuboid sliding section 82 and on which a sealing section 86 is formed. A dome groove 87 extends towards the end face 75 and extends approximately from the valve longitudinal axis 79 to the circumference of the dome 74, which is aligned with the web section 84 and on which the web section 84 with its spray hole disk 51 Lower surface 94 facing away, namely in its non-blocking starting position such that it does not protrude into the guide channel 78. In this starting position, the sealing section 86 which faces away from the dom groove 87 is also in a position in which it rests on the lower end face 54 of the spray hole disk 51, but does not cover any spray hole 53. For example, two spring arms 88 are connected to the web section 84 opposite one another and are slidably mounted in guide grooves 90 formed in the ring edge, as shown in FIG. The spring arms 88 bring about a restoring force which counteracts a displacement movement of the shut-off element from right to left according to FIGS. 3 and 4. The displacement movement of the shut-off element 83 takes place by air force when the pressure force of the air in the air space 67 on the sliding section 82 is greater than the sum of the forces from the spring arms 88 and the pressure force from the individual suction pipe 11 via the guide channels 78 and the gap 76 air acting on the shut-off element 83 in the interior of the spray body 57. By a suitable selection of the spring force of the spring arms 88, it can now be achieved that a displacement of the shut-off element 83 into its position blocking the at least one spray hole 53 and a guide channel 78 to the left only occurs when the air pressure difference between the individual intake pipe is in idle and lower part-load operation of the internal combustion engine 11 and the suction pipe 17 upstream of the throttle valve 18 is large enough for a displacement. As shown in FIG. 1 a, the air space 67 is connected to the intake manifold 17 upstream of the throttle valve 18 and is thus almost at atmospheric pressure. If the throttle valve 18 is rotated more in the opening direction to increase the power of the internal combustion engine, then the pressure increases downstream of the throttle valve 18 and thus also in

Individual suction pipes 11, whereby the restoring force on the shut-off element 83 increases and the shut-off element after is shifted to the right into its starting position, so that the fuel can again be sprayed freely over all spraying holes 53. In order to establish an exact transition point from the shut-off position of the shut-off element 83 to its starting position and thus from the spraying of a single fuel jet to the spraying of at least one further fuel jet and vice versa, it is expedient to arrange a control valve in the air line 23. Such a control valve is already shown in Figures la and 2a to 2c. Starting from the shut-off position in FIG. 2a, the control valve 21 constantly opens the air bypass 19 to the air line 23 until it reaches the position shown in FIG Move the fuel jet interrupting position to the left. If the control valve 21 is rotated further clockwise beyond its position shown in FIG. 2b, the air pressure in the inlet channel 10 increases and the shut-off element 83 is shifted to the right into its open position. The actuation of the shut-off element 83 in the manner described by air is only one possibility. In the same way, it is possible to dispense with the air actuation described and the shut-off element 83 is shown directly by a dashed line in FIG

Electromagnet 91, which is controlled by the electronic control unit 26 to actuate. If the shut-off element 83 is in its shut-off position, then an extension of the spray duration of the fuel injector is controlled via the electronic control unit 26.

In the following Figures 5 to 8, the same and equivalent parts are denoted by the same reference numerals. Figures 5 and 6 show the embodiment of Figures 3 and 4 with an in

Shut-off element 83, which is in its left position and thus at least one Spray hole 53 and a guide channel 78 blocked. The arrows 92 indicate the air flow which passes from the air space 67 past the sliding section 82 displaced from the sliding channel 80 into the interior of the spray body 57 to the gap 76 and there in the left one, which is not blocked off

Guide channel 78 which hits the fuel jet 14 which is sprayed through the at least one unblocked spray hole and is sprayed with it in a conditioning manner.

FIGS. 7 and 8, like FIGS. 5 and 6, also show a fuel injection valve with the described attachment body 42 and a shut-off element 83 which is in the blocking position, but in the embodiment according to FIGS. 7 and 8 the dome 74 is so high that it is on the the lower end face 54 of the spray hole disk 51 bears outside the dome groove 87, while an axial groove gap 95 is formed between the lower surface 94 of the web section 84 and the dome groove 87, via which the gap from the air space 67 in the shut-off position of the shut-off element 83 into the interior of the spray body 57 flowing air can flow into the guide channel 78 assigned to the blocked spray hole 53. Such an embodiment is expedient if the sprayed fuel jet is intended to be a "hard" line jet (pencil stream), that is to say with a very small jet cone angle1.

Claims

1. Fuel injection valve for injecting fuel into an internal combustion engine, wherein at least two separate fuel jets are directed into inlet channels or in the direction of inlet openings of the cylinders of the internal combustion engine controlled by inlet valves, in particular into different inlet channels or inlet openings of a cylinder, characterized in that a shut-off element (83 ) is provided which, depending on the operating conditions of the internal combustion engine (1), can be moved into a position in which it at least interrupts one of the fuel jets (14).

2. Fuel injection valve according to claim 1, characterized in that the shut-off element (83) in a

Injection end (41) of the fuel injection valve (13) arranged attachment body (42) is movably mounted.

3. Fuel injection valve according to claim 2, characterized in that the shut-off element (83) one

Has sealing section (86) which abuts the spray end (41) of the fuel injection valve (13).

4. Fuel injection valve according to claim 2 or 3, characterized in that the shut-off element (83) guer to one

Longitudinal valve axis (79) is displaceable.

5. Fuel injection valve according to claim 4, characterized in that the displacement of the shut-off element

(83) in the direction of an interruption of at least one fuel jet (14) by a fluid or electromagnetically against a restoring force (88).

6. fuel injection valve according to claim 5, characterized in that spring arms (88) are used as the restoring force, which are integrally formed on the shut-off element (83).

7. Fuel injection valve according to claim 6, characterized in that the spring arms (88) in guide grooves (90) of the header body (42) protrude.

8. Fuel injection valve according to claim 3, characterized in that the shut-off element (83) has a sliding section (82) guided in the header (42).

9. fuel injection valve according to claim 2, characterized in that an air line (23) from the intake manifold (17) of the internal combustion engine (1) upstream of a throttle valve (18) leads to the header body (42) and the shut-off element (83) is movable by air.

10. Fuel injection valve according to claim 9, characterized in that the position of the shut-off element (83) in the at least one fuel jet (14) interrupting position moving air in the header body (42) is guided such that it is an uninterrupted fuel jet (14) on the least. meets.

11. Brennεtoffeinεpritzventil according to Anεpruch 10, characterized in that the air line (23) by a control valve (21) is partially or completely closed.

12. Fuel injection valve according to claim 9, characterized in that at the injection end (41) of the fuel injection valve (13) an injection orifice plate (51) with at least two Abεpritzlδchern (53) is provided to form the least two fuel jets (14) and downstream of the injection orifice plate (51 ) Guide channels (78) penetrate the front body (42) through which a fuel jet (14) can be sprayed.

13. Fuel injection valve according to claim 12, characterized in that through the shut-off element (83) at least at least one spray hole (53) of the spray hole disc (51) and a guide channel (78) in the front body (42) can be blocked.

14. Fuel injection valve according to claim 12, characterized in that at least one spray hole (53) of the spray hole disc (51) can be blocked by the shut-off element (83) and the air can only be conducted via the guide channel (78) assigned to it.

15. Fuel injection valve according to claim 11, characterized in that alε control valve (21) is a so-called

Idle control valve is used, which controls an air bypass (19) around the throttle valve (18) for idle control of the internal combustion engine (1).